Introduction: Isokinetic dynamometry is a reliable measuring method for evaluating peak torques of the knee flexor and extensor muscles across various types of contraction and velocities of movement. To assess balance of antagonistic muscle groups of the knee, the conventional (concentric and eccentric) and functional ratios of their maximum torques (H:Q) are usually calculated. However, the H:Q are not constant values, since change is depending on the velocity of muscle contraction, they are presumably also influenced by gender. Purpose: To study the performance of knee flexor and extensor muscles during concentric and eccentric contractions in healthy young adults. We were particularly interested in the influence of gender and muscle contraction velocity on conventional and functional H:Q ratios. Methods: The study was conducted on a sample of 31 healthy young adults of both genders (age: 20-31 years). A computer-driven isokinetic dynamometer was used to measure the maximum concentric and eccentric peak torques of the knee flexors and extensors at three different angular velocities (60°/s, 180°/s, 240°/s), and to calculate conventional and functional H:Q ratios. Paired t-test and factorial ANOVA were used for statistical analysis. Results: The eccentric peak torques were statistically significantly (p<0,01) higher at all angular velocities regardless of gender. The concentric peak torques of both muscle groups decreased inversely with angular velocity (p < 0,001). Eccentric and concentric peak torques normalized to body mass were higher in men (p<0,05), while the interaction between gender and angular velocity was not statistically significant. There was no statistically significant difference between genders in concentric and functional H:Q ratios, whereas women had lower (p=0,020) eccentric peak torque H:Q ratios than men. The interaction between gender and joint angular velocity was not statistically significant for any of the H:Q ratios. Discussion and conclusion: There are some differences between genders in peak torques of both knee muscle groups and their eccentric H:Q ratios. Other H:Q ratios do not differ between genders in the studied range of muscle contraction rates. We recommend expanding the range of contraction velocities to >240°/s and calculate H:Q ratios depending on joint position in future research.
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